In Vitro Activity and Clinical Efficacy of Faropenem against Third-Generation Cephalosporin-Resistant Escherichia coli and Klebsiella pneumoniae.

Faropenem (FRPM) is active against extended-spectrum ß-lactamase (ESBL)-producing Enterobacterales, but evidence for its efficacy is lacking. This study determined the correlation between the susceptibility by disk diffusion method and the MIC of FRPM for third-generation cephalosporin-resistant Escherichia coli and Klebsiella pneumoniae, and the effectiveness of FRPM for the treatment of urinary tract infection (UTI) caused by these two bacteria in a retrospective cohort analysis. Of the 48 third-generation cephalosporin-resistant clinical isolates tested, 44 isolates produced ESBL, and 8 isolates produced AmpC, including 4 isolates produced both ESBL and AmpC. Thirty-seven isolates had an FRPM MIC of ≤1 mg/L, and seven had an FRPM MIC of 2 mg/L. An FRPM MIC of >2 mg/L was observed with four isolates. In a retrospective cohort analysis, 63 patients with UTI treated with FRPM were identified. All isolates of ESBL-producing E. coli (n = 54) and K. pneumoniae (n = 9) treated with FRPM showed disk diffusion zone diameters larger than 16.0 mm (estimated MIC, 2.2 mg/L). All patients completed the scheduled treatment courses with FRPM, but 28- and 90-day relapses happened in 10 patients (16%) and 16 patients (25%), respectively. No significant risk factors for the 28- and 90-day relapses were found. FRPM can be used according to disk diffusion susceptibility testing in UTI. Further investigations are necessary to assess the clinical breakpoint of FRPM for ESBL-producing Enterobacterales and the candidates most likely to benefit from using FRPM.

Modulation of viability of live cells by focused ion-beam exposure.

Introduction of membrane-impermeant substances into living cells is the key method to understand contemporary cellular processes by investigating cellular responses and phenotypes. Here, we performed gold ion beam exposure into live cells by using the focused ion beam implantation method, which was originally developed to precisely control semiconductor device performances. We evaluated the viability of the gold-irradiated cells by measuring the concentration of adenosine triphosphate (ATP), which is an intracellular energy source produced in the mitochondrial membrane. The viability of the irradiated cells was found to be 20% higher than that of the unirradiated control cells. The atoms might promote the energy generating processes within the mitochondrion. Our results suggest that the viability of living cells can be modulated by accurately controlling the dopant atom numbers. Our technique may be considered as a potential tool in life and medical sciences to quantitatively elucidate the dose-dependent effects of dopants.